Does anyone know what this engine noise indicates?

Background;
-It’s an early 2004 xc90, 2.5T, petrol, 180K miles.
-I got the faulty message ”low oil pressure, stop the engine safely”, and the engine sounded like in the link above.
-There was enough oil in the engine (no leak).
-The message only showed up when the engine was warm.
-After changing the oil and the filter, the message “disappeared”, even when the engine was warm. The noise also disappeared.
-After a while, the message reappeared. But no strange engine noise.
-Now the engine won’t even crank. There is enough oil, still no leak. And I’m also getting a new faulty message “reduced engine performance”.

The mechanic is said that the crankshaft is probably damaged due to the low oil pressure, and it’s better to replace the engine than repairing it (how shocking..) because the repair would cost as much as replacing it.

what do you guys think the problem is?

 

Sorry to hear about the issues!
I would say perhaps though there was oil in the engine, it probably was not circulating properly.
If it is not even turning over now after getting multiple "low oil pressure" warnings I would guess you probably have seized the motor... in which case a replacement may be easier as the mechanic said.
Did you notice the engine overheating?
Maybe get a second opinion?